The conventional methods of making package containers filled with liquid foodstuffs (including fluid products), such as milk, involve vertically sealing a web of packaging material, made of a flexible laminate, into a tubular form, then filling the tubular packaging material with the liquid foodstuff and, at the same time, laterally sealing the tubular packaging material.
FIG. 2 schematically shows an example of a filling and packaging apparatus with which such containers are made. The exemplified packaging and filling apparatus draws out a web 41 of packaging material having layers of thermoplastic resin as its internal and external layers wrapped in the form of a roll, and conveys the web 41 of packaging material within the packaging and filling apparatus by means of rollers. A strip of tape is joined to one edge of the web of packaging material by a strip tape applicator 43. Subsequently, the web 41 of packaging material is passed through a sterilizing liquid tank 44 to undergo sterilization. A squeeze roller and air knife 45 remove any sterilizing liquid remaining on the surface of the packaging material.
Next, forming rollers 46 form the above-described web of packaging material into a tube. One edge of the packaging material is covered with the other to form an overlap. A vertical seal element 42 vertically seals the overlap in the direction of the length of the tube. Then, the tube is filled with a liquid foodstuff from a filling pipe 47. While conveyed downward by a distance corresponding to the length of one packaging container, the tube is grasped between a sealing jaw and opposite jaw of each lateral sealing device 48. Lateral seal bands are formed by sealing the tube in the direction in which the bands intersect the tube, and thus a series of pillow-like preformed bodies 49 are formed at the same time. A cutting device (not shown) such as a knife cuts the middle of each lateral seal band between the pillow-like preformed bodies, thereby severing the pillow-like preformed bodies 49 from each other. Thus, packaging containers filled with the liquid foodstuff, which have the final form, are made.
FIG. 3 shows in detail a partial section of the lateral sealing device 48 and cutting device 32. In the embodiment, while conveyed downward by the distance corresponding to the length of one packaging material, the tubular packaging material 41 filled with the foodstuff is grasped by two pairs of forming flaps 31 so as to be formed into the approximate shape of the container. The tubular packaging material 41 is also grasped by the two pairs of sealing jaws 48 and opposite jaws 48. The two pairs form the lateral seal bands by sealing the tube in the direction in which the bands intersect the tube. Next, each seal band connecting the pillow-like preformed bodies is cut through the middle with the knife 33 of the cutting device 32, thereby severing the pillow-like preformed bodies 49 from each other. The knife 33 of the cutting device 32 has a cutting mechanism driven by a pressure medium (e.g., oil pressure, air pressure).
Patent Document 1: Japanese Patent Application Laid-Open No. 07-24938